# Package net.sf.saxon.s9api

This package provides Saxon's preferred Java API for XSLT, XQuery, XPath, and XML Schema processing.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  BuildingContentHandler | A SAX `ContentHandler` that builds a Saxon tree, and allows the node at the root of the tree to be retrieved on completion.
  BuildingStreamWriter | A BuildingStreamWriter allows a document to be constructed by calling the methods defined in the `XMLStreamWriter` interface; after the document has been constructed, its root node may be retrieved by calling the `getDocumentNode()` method.
  Destination | A Destination represents a place where XML can be sent.
  ExtensionFunction | This is an interface for simple external/extension functions.
  MessageListener | A user-written implementation of the MessageListener interface may be registered with the XsltTransformer to receive notification of xsl:message output.

- Class Summary
  Class | Description
  --- | ---
  BuildingStreamWriterImpl | This class is an implementation of `XMLStreamWriter`, allowing a document to be constructed by means of a series of XMLStreamWriter method calls such as writeStartElement(), writeAttribute(), writeCharacters(), and writeEndElement().
  DocumentBuilder | A document builder holds properties controlling how a Saxon document tree should be built, and provides methods to invoke the tree construction.
  DOMDestination | This class represents a Destination (for example, the destination of the output of a transformation) in which the results are written to a newly constructed DOM tree in memory.
  ItemType | An item type, as defined in the XPath/XQuery specifications.
  ItemTypeFactory | This class is used for creating ItemType objects.
  Processor | The `Processor` class serves three purposes: it allows global Saxon configuration options to be set; it acts as a factory for generating XQuery, XPath, and XSLT compilers; and it owns certain shared resources such as the Saxon NamePool and compiled schemas.
  QName | The QName class represents an instance of xs:QName, as defined in the XPath 2.0 data model.
  SAXDestination | This class represents a Destination (for example, the destination of the output of a transformation) in which events representing the XML document are sent to a user-supplied SAX2 ContentHandler, as if the ContentHandler were receiving the document directly from an XML parser.
  SchemaManager | The SchemaManager is used to load schema documents, and to set options for the way in which they are loaded.
  SchemaValidator | A `SchemaValidator` is an object that is used for validating instance documents against a schema.
  SequenceType | A SequenceType is the combination of an ItemType and an OccurrenceIndicator
  Serializer | A Serializer takes a tree representation of XML and turns it into lexical XML markup.
  TeeDestination | A TeeDestination allows writing to two destinations at once.
  WhitespaceStrippingPolicy | WhitespaceStrippingPolicy is class defining the possible policies for handling whitespace text nodes in a source document.
  XdmAtomicValue | The class XdmAtomicValue represents an item in an XPath 2.0 sequence that is an atomic value.
  XdmDestination | An `XdmDestination` is a `Destination` in which an `XdmNode` is constructed to hold the output of a query or transformation: that is, a tree using Saxon's implementation of the XDM data model
  XdmEmptySequence | The class `XdmEmptySequence` represents an empty sequence in the XDM Data Model.
  XdmExternalObject | The class XdmExternalObject represents an XDM item that wraps an external (Java or .NET) object.
  XdmFunctionItem | The class XdmFunctionItem represents a function item
  XdmItem | The class XdmItem represents an item in a sequence, as defined by the XDM data model.
  XdmNode | This class represents a node in the XDM data model.
  XdmSequenceIterator | An iterator over an XPath sequence.
  XdmValue | An value in the XDM data model.
  XPathCompiler | An XPathCompiler object allows XPath queries to be compiled.
  XPathExecutable | An XPathExecutable represents the compiled form of an XPath expression.
  XPathSelector | An XPathSelector represents a compiled and loaded XPath expression ready for execution.
  XQueryCompiler | An XQueryCompiler object allows XQuery 1.0 queries to be compiled.
  XQueryEvaluator | An `XQueryEvaluator` represents a compiled and loaded query ready for execution.
  XQueryExecutable | An XQueryExecutable represents the compiled form of a query.
  XsltCompiler | An XsltCompiler object allows XSLT 2.0 stylesheets to be compiled.
  XsltExecutable | An XsltExecutable represents the compiled form of a stylesheet.
  XsltTransformer | An `XsltTransformer` represents a compiled and loaded stylesheet ready for execution.

- Enum Summary
  Enum | Description
  --- | ---
  Axis | This is an enumeration class containing constants representing the thirteen XPath axes
  OccurrenceIndicator | Represents one of the possible occurrence indicators in a SequenceType.
  Serializer.Property | Enumerator over the defined serialization properties
  ValidationMode | Enumeration class defining different schema validation (or construction) modes
  XdmNodeKind | Enumeration class defining the seven kinds of node defined in the XDM model

- Exception Summary
  Exception | Description
  --- | ---
  SaxonApiException | An exception thrown by the Saxon s9api API.
  SaxonApiUncheckedException | An unchecked exception thrown by the Saxon API.

## Package net.sf.saxon.s9api Description

This package provides Saxon's preferred Java API for XSLT, XQuery, XPath, and XML Schema processing. The interface is designed to hide as much as possible of the detail of the implementation. However, the API architecture faithfully reflects the internal architecture of the Saxon product, unlike standard APIs such as JAXP and XQJ which in many cases force compromises in the design and performance of the application.

An application starts by loading a `Processor`, which allows configuration options to be set. As far as possible, an application should instantiate a single `Processor`.

The interfaces for XSLT, XQuery, and XPath processing all follow the same pattern. There is a three-stage execution model: first a compiler is created using a factory method in the `Processor` object. The compiler holds compile-time options and the static context information. Then the compiler's `compile()` method is called to create an executable, a representation of the compiled stylesheet, query, or expression. This is thread-safe and immutable once created. To run the query or transformation, first call the `load()` method to create a run-time object called variously an `XsltTransformer`, `XQueryEvaluator`, or `XPathSelector`. This holds run-time context information such as parameter settings and the initial context node; the object is therefore not shareable and should only be run in a single thread; indeed it should normally only be used once. This object also provides methods allowing the transformation or query to be executed.

In Saxon-EE the `Processor` owns a `SchemaManager` that holds the cache of schema components and can be used to load new schema components from source schema documents. It can also be used to create a `SchemaValidator`, which in turn is used to validate instance documents.

Source documents can be constructed using a `DocumentBuilder`, which holds all the options and parameters to control document building.

The output of a transformation, or of any other process that generates an XML tree, can be sent to a `Destination`. There are a number of implementations of this interface, including a `Serializer` which translates the XML document tree into lexical XML form.

There are classes to represent the objects of the XDM data model, including `XdmValue`, `XdmItem`, `XdmNode`, and `XdmAtomicValue`.

The s9api interface is designed to take advantage of Java 5 constructs such as generics and iterables.

Michael H. Kay
Saxonica Limited
30 July 2010

Copyright (c) 2004-2013 Saxonica Limited. All rights reserved.